Eric Adams, the Brooklyn borough president, said the Police Department should have released details about the attack earlier. Photo: The New York Times

The police said the five young men, one of them armed, walked up to the father and daughter in Osborn Playground just after 9pm on Thursday.

The father and daughter told the police they had been at the playground drinking beer.

The father ran to get help, but the police official said it took him roughly 20 minutes to come upon two uniformed police officers on patrol. By the time the father returned to the playground with the officers, the young men had each raped the woman and fled, the official said.

In an area filled with public housing high-rises, delis and other stores, it is unclear why the father was not able to get help from bystanders or call the police from a store. The police said there was no evidence of any 911 calls being placed in connection with the attack.

The officers called for an ambulance when they arrived, and the woman was taken to Kings County Hospital Centre for treatment.

Without other witnesses, investigators began canvassing the area on Friday for video, starting with subway stations and businesses and expanding outward, a police official said.

They also conducted a second, more detailed, interview with the woman. On Saturday afternoon, investigators found the surveillance video that they released that night.

Mateo Gomez, an attendant at Laida Deli, said that the footage came from his shop and that he recognised the suspects as young men who came to the store most afternoons, sometimes stealing cakes and other snacks.

"They're bad boys," he said.

Some neighbours said they knew the playground as a dangerous, late-night hangout spot, although even they said they were shocked by the assault.

The public space has turquoise and red climbing equipment, fenced-in basketball and handball courts and a blacktop softball field, all arranged between a public school and a block of low-rise homes.

On Sunday morning, there was a condom on the ground, near a smashed bottle of vodka, in a secluded corner between a handball wall and a backyard fence.

Several residents, including Ms Pierce, complained that the park lights were rarely on at night.

She already took precautions, carrying a small pocketknife for safety on her way to work past the playground. She called the attack "devastating".

The New York City parks department said it was working with the Transportation Department, which maintains park lights, to inspect the lighting.

Other neighbours were upset they had not learnt of the attack sooner.

"Why are we only just hearing about this yesterday?" said Kakeshia Taylor, 27, a mother of three. "This is breaking news. We need to know what's happening in our neighbourhood."

In a statement issued on Sunday, mayor Bill de Blasio said he was "disgusted and extremely saddened by the horrific attack."

He added: "Every New Yorker in every neighbourhood deserves to feel safe and protected, and we will not stop until the perpetrators of this disturbing attack are held accountable for their actions."

Some elected officials expressed concern about what they called an unusually long period before a public notice went out.

Eric Adams, the Brooklyn borough president, said that, as a matter of public safety, the Police Department erred in not releasing details of the crime to the public until Saturday night, after nearly 48 hours had passed.

"The NYPD should have reported this immediately," said Mr Adams, who is a former New York City police captain.

"You can't have a crime of this magnitude and this level of savage behaviour and not have the residents of that area become aware of what happened."

The Police Department official said the local precinct commander had reached out to local leaders about the attack on Friday. He said the department generally released public notices after finding and processing video or other leads.

In cases where a pattern of criminal behaviour and a continuing threat might exist, a notice might be released sooner.

The Police Department said in a statement on Sunday night that the officers who were alerted by the father "immediately responded and located the victim" before calling for a supervisor and an ambulance.

"There was no delay in responding to the rape," the statement said.

Bernard Briggs, 54, a bus driver, said he came to fear young men who typically fill the playground at night after a run-in a few weeks ago.

He had gone to use the men's room when three men broke away from a group playing basketball to charge the bathroom door, trying to trap Mr Briggs inside. Mr Briggs said he fought his way out.

"There's always young guys in this section; if they feel you're vulnerable they come after you," Mr Briggs said.